Please read my post carefuly before replying hastily. I know it was rather long sorry ;-)
All I said was that the menu accounts / my google account / sync should reflect reality! Now what happens is that when you switch to medium or max power savings the synchronization of those thigs is essentialy switched off, but it might seem it is still on because all those toggles remain on! I think that sync settings menu is basically lying in this situation and that's what can be easily fixed IMHO.
Example code: if the calendar sync service is sleeping or stopped then switch the toggle calendar sync off.
I did NOT select a power savings mode because I don't have difficulty charging my phone throughout the day when needed.
And even if I did, my phone was on 90% charge the last time I tried to manually sync, (several times,) so this optimization feature is buggy or beyond typical/advanced user comprehension on the s10e.
ADDITIONAL SOLUTION: What I found after much frustraion is I had to go to my default app Calendar, press the 3 lines in upper left corner, under Calendars - press the little down arrow beside your google calendar and you will find several sub-calendars, ensure that all the correct calendars are ticked.
In my case I had subscribed to an external calendar (chiro appointments) through my google calendar, so this had created a new sub-calendar within my google calendar. I had to go in as above and tick this new calendar so that it would sync with my samsung default app calendar.
Hope this helps you.